1 <!-- ##### SECTION Title ##### -->
4 <!-- ##### SECTION Short_Description ##### -->
5 The GLib Runtime type identification and management system
7 <!-- ##### SECTION Long_Description ##### -->
9 The GType API is the foundation of the GObject system. It provides the
10 facilities for registering and managing all fundamental data types,
11 user-defined object and interface types. Before using any GType
12 or GObject functions, g_type_init() must be called to initialize the
16 For type creation and registration purposes, all types fall into one of
17 two categories: static or dynamic. Static types are never loaded or
18 unloaded at run-time as dynamic types may be. Static types are created
19 with g_type_register_static() that gets type specific information passed
20 in via a #GTypeInfo structure.
21 Dynamic types are created with g_type_register_dynamic() which takes a
22 #GTypePlugin structure instead. The remaining type information (the
23 #GTypeInfo structure) is retrieved during runtime through #GTypePlugin
24 and the g_type_plugin_*() API.
25 These registration functions are usually called only once from a
26 function whose only purpose is to return the type identifier for a
27 specific class. Once the type (or class or interface) is registered,
28 it may be instantiated, inherited, or implemented depending on exactly
29 what sort of type it is.
30 There is also a third registration function for registering fundamental
31 types called g_type_register_fundamental() which requires both a #GTypeInfo
32 structure and a #GTypeFundamentalInfo structure but it is seldom used
33 since most fundamental types are predefined rather than user-defined.
36 A final word about type names.
37 Such an identifier needs to be at least three characters long. There is no
38 upper length limit. The first character needs to be a letter (a-z or A-Z)
39 or an underscore '_'. Subsequent characters can be letters, numbers or
43 <!-- ##### SECTION See_Also ##### -->
48 <!-- ##### SECTION Stability_Level ##### -->
51 <!-- ##### TYPEDEF GType ##### -->
53 A numerical value which represents the unique identifier of a registered
58 <!-- ##### MACRO G_TYPE_FUNDAMENTAL ##### -->
60 Returns the fundamental type which is the ancestor of @type.
61 Fundamental types are types that serve as fundaments for the derived types,
62 thus they are the roots of distinct inheritance hierarchies.
65 @type: A #GType value.
68 <!-- ##### MACRO G_TYPE_FUNDAMENTAL_MAX ##### -->
70 An integer constant that represents the number of identifiers reserved
71 for types that are assigned at compile-time.
76 <!-- ##### MACRO G_TYPE_MAKE_FUNDAMENTAL ##### -->
78 Returns the type ID for the fundamental type number @x.
79 Use g_type_fundamental_next() instead of this macro to create new fundamental
83 @x: the fundamental type number.
86 <!-- ##### MACRO G_TYPE_IS_ABSTRACT ##### -->
88 Returns %TRUE if @type is an abstract type. An abstract type can not be
89 instantiated and is normally used as an abstract base class for
93 @type: A #GType value.
96 <!-- ##### MACRO G_TYPE_IS_DERIVED ##### -->
98 Returns %TRUE if @type is derived (or in object-oriented terminology:
99 inherited) from another type (this holds true for all non-fundamental
103 @type: A #GType value.
106 <!-- ##### MACRO G_TYPE_IS_FUNDAMENTAL ##### -->
108 Returns %TRUE if @type is a fundamental type.
111 @type: A #GType value.
114 <!-- ##### MACRO G_TYPE_IS_VALUE_TYPE ##### -->
116 Returns %TRUE if @type is a value type which can be used for
120 @type: A #GType value.
123 <!-- ##### MACRO G_TYPE_HAS_VALUE_TABLE ##### -->
125 Returns %TRUE if @type has a #GTypeValueTable.
128 @type: A #GType value.
131 <!-- ##### MACRO G_TYPE_IS_CLASSED ##### -->
133 Returns %TRUE if @type is a classed type.
136 @type: A #GType value.
139 <!-- ##### MACRO G_TYPE_IS_INSTANTIATABLE ##### -->
141 Returns %TRUE if @type can be instantiated. Instantiation is the
142 process of creating an instance (object) of this type.
145 @type: A #GType value.
148 <!-- ##### MACRO G_TYPE_IS_DERIVABLE ##### -->
150 Returns %TRUE if @type is a derivable type. A derivable type can
151 be used as the base class of a flat (single-level) class hierarchy.
154 @type: A #GType value.
157 <!-- ##### MACRO G_TYPE_IS_DEEP_DERIVABLE ##### -->
159 Returns %TRUE if @type is a deep derivable type. A deep derivable type
160 can be used as the base class of a deep (multi-level) class hierarchy.
163 @type: A #GType value.
166 <!-- ##### MACRO G_TYPE_IS_INTERFACE ##### -->
168 Returns %TRUE if @type is an interface type.
169 Interface types are types that provide pure APIs, the implementation
170 of which is provided by another type (which is then said to conform
171 to the interface). GLib interfaces are somewhat analogous to Java
172 interfaces and C++ classes containing only pure virtual functions,
173 with the difference that GType interfaces are not derivable (but see
174 g_type_interface_add_prerequisite() for an alternative).
177 @type: A #GType value.
180 <!-- ##### STRUCT GTypeInterface ##### -->
182 An opaque structure used as the base of all interface types.
186 <!-- ##### STRUCT GTypeInstance ##### -->
188 An opaque structure used as the base of all type instances.
192 <!-- ##### STRUCT GTypeClass ##### -->
194 An opaque structure used as the base of all classes.
198 <!-- ##### STRUCT GTypeInfo ##### -->
200 This structure is used to provide the type system with the information
201 required to initialize and destruct (finalize) a type's class and
203 The initialized structure is passed to the g_type_register_static() function
204 (or is copied into the provided #GTypeInfo structure in the
205 g_type_plugin_complete_type_info()). The type system will perform a deep
206 copy of this structure, so it's memory does not need to be persistent
207 across invocation of g_type_register_static().
210 @class_size: Size of the class structure (required for interface, classed and instantiatable types).
211 @base_init: Location of the base initialization function (optional).
212 @base_finalize: Location of the base finalization function (optional).
213 @class_init: Location of the class initialization function for
214 classed and types. Location of the default vtable inititalization
215 function for interface types. (optional) This function is used both
216 to fill in virtual functions in the class or default vtable, and
217 to do type-specific setup such as registering signals and object
219 @class_finalize: Location of the class finalization function for
220 classed and types. Location fo the default vtable finalization
221 function for interface types. (optional)
222 @class_data: User-supplied data passed to the class init/finalize functions.
223 @instance_size: Size of the instance (object) structure (required for instantiatable types only).
224 @n_preallocs: Prior to GLib 2.10, it specified the number of pre-allocated (cached) instances to reserve memory for (0 indicates no caching). Since GLib 2.10, it is ignored, since instances are allocated with the <link linkend="glib-Memory-Slices">slice allocator</link> now.
225 @instance_init: Location of the instance initialization function (optional, for instantiatable types only).
226 @value_table: A #GTypeValueTable function table for generic handling of GValues of this type (usually only
227 useful for fundamental types).
229 <!-- ##### STRUCT GTypeFundamentalInfo ##### -->
231 A structure that provides information to the type system which is
232 used specifically for managing fundamental types.
235 @type_flags: #GTypeFundamentalFlags describing the characteristics of the fundamental type
237 <!-- ##### STRUCT GInterfaceInfo ##### -->
239 A structure that provides information to the type system which is
240 used specifically for managing interface types.
243 @interface_init: Location of the function that initializes the interface.
244 @interface_finalize: Location of the function that finalizes the interface.
245 @interface_data: Location of user data passed to the @interface_init and
246 @interface_finalize functions (optional).
248 <!-- ##### STRUCT GTypeValueTable ##### -->
250 The #GTypeValueTable provides the functions required by the #GValue implementation,
251 to serve as a container for values of a type.
254 @value_init: Default initialize @values contents by poking values
255 directly into the value->data array. The data array of
256 the #GValue passed into this function was zero-filled
257 with <function>memset()</function>, so no care has to
259 old contents. E.g. for the implementation of a string
260 value that may never be %NULL, the implementation might
264 value->data[0].v_pointer = g_strdup ("");
267 @value_free: Free any old contents that might be left in the
268 data array of the passed in @value. No resources may
269 remain allocated through the #GValue contents after
270 this function returns. E.g. for our above string type:
273 /* only free strings without a specific flag for static storage */
274 if (!(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
275 g_free (value->data[0].v_pointer);
278 @value_copy: @dest_value is a #GValue with zero-filled data section
279 and @src_value is a properly setup #GValue of same or
281 The purpose of this function is to copy the contents of
282 @src_value into @dest_value in a way, that even after
283 @src_value has been freed, the contents of @dest_value
284 remain valid. String type example:
287 dest_value->data[0].v_pointer = g_strdup (src_value->data[0].v_pointer);
290 @value_peek_pointer: If the value contents fit into a pointer, such as objects
291 or strings, return this pointer, so the caller can peek at
292 the current contents. To extend on our above string example:
295 return value->data[0].v_pointer;
298 @collect_format: A string format describing how to collect the contents of
299 this value, bit-by-bit. Each character in the format represents
300 an argument to be collected, the characters themselves indicate
301 the type of the argument. Currently supported arguments are:
303 <varlistentry><term></term><listitem><para>
304 'i' - Integers. passed as collect_values[].v_int.
305 </para></listitem></varlistentry>
306 <varlistentry><term></term><listitem><para>
307 'l' - Longs. passed as collect_values[].v_long.
308 </para></listitem></varlistentry>
309 <varlistentry><term></term><listitem><para>
310 'd' - Doubles. passed as collect_values[].v_double.
311 </para></listitem></varlistentry>
312 <varlistentry><term></term><listitem><para>
313 'p' - Pointers. passed as collect_values[].v_pointer.
314 </para></listitem></varlistentry>
316 It should be noted, that for variable argument list construction,
317 ANSI C promotes every type smaller than an integer to an int, and
318 floats to doubles. So for collection of short int or char, 'i'
319 needs to be used, and for collection of floats 'd'.
320 @collect_value: The collect_value() function is responsible for converting the
321 values collected from a variable argument list into contents
322 suitable for storage in a GValue. This function should setup
323 @value similar to value_init(), e.g. for a string value that
324 does not allow %NULL pointers, it needs to either spew an error,
325 or do an implicit conversion by storing an empty string.
326 The @value passed in to this function has a zero-filled data
327 array, so just like for value_init() it is guaranteed to not
328 contain any old contents that might need freeing.
329 @n_collect_values is exactly the string length of @collect_format,
330 and @collect_values is an array of unions #GTypeCValue with
331 length @n_collect_values, containing the collected values
332 according to @collect_format.
333 @collect_flags is an argument provided as a hint by the caller,
334 which may contain the flag #G_VALUE_NOCOPY_CONTENTS indicating,
335 that the collected value contents may be considered "static"
336 for the duration of the @value lifetime.
337 Thus an extra copy of the contents stored in @collect_values is
338 not required for assignment to @value.
339 For our above string example, we continue with:
342 if (!collect_values[0].v_pointer)
343 value->data[0].v_pointer = g_strdup ("");
344 else if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
346 value->data[0].v_pointer = collect_values[0].v_pointer;
347 /* keep a flag for the value_free() implementation to not free this string */
348 value->data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
351 value->data[0].v_pointer = g_strdup (collect_values[0].v_pointer);
356 It should be noted, that it is generally a bad idea to follow the
357 #G_VALUE_NOCOPY_CONTENTS hint for reference counted types. Due to
358 reentrancy requirements and reference count assertions performed
359 by the #GSignal code, reference counts should always be incremented
360 for reference counted contents stored in the value->data array.
361 To deviate from our string example for a moment, and taking a look
362 at an exemplary implementation for collect_value() of #GObject:
365 if (collect_values[0].v_pointer)
367 GObject *object = G_OBJECT (collect_values[0].v_pointer);
369 /* never honour G_VALUE_NOCOPY_CONTENTS for ref-counted types */
370 value->data[0].v_pointer = g_object_ref (object);
374 return g_strdup_printf ("Object passed as invalid NULL pointer");
377 The reference count for valid objects is always incremented,
378 regardless of @collect_flags. For invalid objects, the example
379 returns a newly allocated string without altering @value.
380 Upon success, collect_value() needs to return %NULL, if however
381 a malicious condition occurred, collect_value() may spew an
382 error by returning a newly allocated non-%NULL string, giving
383 a suitable description of the error condition.
384 The calling code makes no assumptions about the @value
385 contents being valid upon error returns, @value
386 is simply thrown away without further freeing. As such, it is
387 a good idea to not allocate #GValue contents, prior to returning
388 an error, however, collect_values() is not obliged to return
389 a correctly setup @value for error returns, simply because
390 any non-%NULL return is considered a fatal condition so further
391 program behaviour is undefined.
392 @lcopy_format: Format description of the arguments to collect for @lcopy_value,
393 analogous to @collect_format. Usually, @lcopy_format string consists
394 only of 'p's to provide lcopy_value() with pointers to storage locations.
395 @lcopy_value: This function is responsible for storing the @value contents into
396 arguments passed through a variable argument list which got
397 collected into @collect_values according to @lcopy_format.
398 @n_collect_values equals the string length of @lcopy_format,
399 and @collect_flags may contain #G_VALUE_NOCOPY_CONTENTS.
400 In contrast to collect_value(), lcopy_value() is obliged to
401 always properly support #G_VALUE_NOCOPY_CONTENTS.
402 Similar to collect_value() the function may prematurely abort
403 by returning a newly allocated string describing an error condition.
404 To complete the string example:
407 gchar **string_p = collect_values[0].v_pointer;
410 return g_strdup_printf ("string location passed as NULL");
412 if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
413 *string_p = value->data[0].v_pointer;
415 *string_p = g_strdup (value->data[0].v_pointer);
419 And an exemplary version of lcopy_value() for
420 reference-counted types:
423 GObject **object_p = collect_values[0].v_pointer;
426 return g_strdup_printf ("object location passed as NULL");
427 if (!value->data[0].v_pointer)
429 else if (collect_flags & G_VALUE_NOCOPY_CONTENTS) /* always honour */
430 *object_p = value->data[0].v_pointer;
432 *object_p = g_object_ref (value->data[0].v_pointer);
437 <!-- ##### MACRO G_TYPE_FROM_INSTANCE ##### -->
439 Returns the type identifier from a given @instance structure.
442 This macro should only be used in type implementations.
445 @instance: Location of a valid #GTypeInstance structure.
448 <!-- ##### MACRO G_TYPE_FROM_CLASS ##### -->
450 Returns the type identifier from a given @class structure.
453 This macro should only be used in type implementations.
456 @g_class: Location of a valid #GTypeClass structure.
459 <!-- ##### MACRO G_TYPE_FROM_INTERFACE ##### -->
461 Returns the type identifier from a given @interface structure.
464 This macro should only be used in type implementations.
467 @g_iface: Location of a valid #GTypeInterface structure.
470 <!-- ##### MACRO G_TYPE_INSTANCE_GET_CLASS ##### -->
472 Returns the class structure of a given @instance, casted
473 to a specified ancestor type @g_type of the instance.
476 that while calling a GInstanceInitFunc(), the class pointer gets
477 modified, so it might not always return the expected pointer.
480 This macro should only be used in type implementations.
483 @instance: Location of the #GTypeInstance structure.
484 @g_type: The anchestor type of the class to be returned.
485 @c_type: The corresponding C type of @g_type.
488 <!-- ##### MACRO G_TYPE_INSTANCE_GET_INTERFACE ##### -->
490 Returns the interface structure for interface @g_type of a given @instance.
493 This macro should only be used in type implementations.
496 @instance: Location of the #GTypeInstance structure.
497 @g_type: The interface type to be returned.
498 @c_type: The corresponding C type of @g_type.
501 <!-- ##### MACRO G_TYPE_INSTANCE_GET_PRIVATE ##### -->
503 Gets the private structure for a particular type.
504 The private structure must have been registered in the
505 class_init function with g_type_class_add_private().
508 This macro should only be used in type implementations.
511 @instance: the instance of a type deriving from @private_type.
512 @g_type: the type identifying which private data to retrieve.
513 @c_type: The C type for the private structure.
516 <!-- ##### MACRO G_TYPE_CHECK_INSTANCE ##### -->
518 Returns %TRUE if @instance is a valid #GTypeInstance structure,
519 otherwise emits a warning and returns %FALSE.
522 This macro should only be used in type implementations.
525 @instance: Location of a #GTypeInstance structure.
528 <!-- ##### MACRO G_TYPE_CHECK_INSTANCE_CAST ##### -->
530 Checks that @instance is an instance of the type identified by @g_type
531 and emits a warning if this is not the case. Returns @instance casted
532 to a pointer to @c_type.
535 This macro should only be used in type implementations.
538 @instance: Location of a #GTypeInstance structure.
539 @g_type: The type to be returned.
540 @c_type: The corresponding C type of @g_type.
543 <!-- ##### MACRO G_TYPE_CHECK_INSTANCE_TYPE ##### -->
545 Returns %TRUE if @instance is an instance of the type identified by @g_type.
546 Otherwise emits a warning and returns %FALSE.
549 This macro should only be used in type implementations.
552 @instance: Location of a #GTypeInstance structure.
553 @g_type: The type to be checked
556 <!-- ##### MACRO G_TYPE_CHECK_CLASS_CAST ##### -->
558 Checks that @g_class is a class structure of the type identified by @g_type
559 and emits a warning if this is not the case. Returns @g_class casted
560 to a pointer to @c_type.
563 This macro should only be used in type implementations.
566 @g_class: Location of a #GTypeClass structure.
567 @g_type: The type to be returned.
568 @c_type: The corresponding C type of class structure of @g_type.
571 <!-- ##### MACRO G_TYPE_CHECK_CLASS_TYPE ##### -->
573 Returns %TRUE if @g_class is a class structure of the type identified by
574 @g_type. Otherwise emits a warning and returns %FALSE.
577 This macro should only be used in type implementations.
580 @g_class: Location of a #GTypeClass structure.
581 @g_type: The type to be checked.
584 <!-- ##### MACRO G_TYPE_CHECK_VALUE ##### -->
586 Returns %TRUE if @value has been initialized to hold values
590 This macro should only be used in type implementations.
596 <!-- ##### MACRO G_TYPE_CHECK_VALUE_TYPE ##### -->
598 Returns %TRUE if @value has been initialized to hold values
602 This macro should only be used in type implementations.
606 @g_type: The type to be checked.
609 <!-- ##### MACRO G_TYPE_FLAG_RESERVED_ID_BIT ##### -->
611 A bit in the type number that's supposed to be left untouched.
616 <!-- ##### FUNCTION g_type_init ##### -->
618 Prior to any use of the type system, g_type_init() has to be called to initialize
619 the type system and assorted other code portions (such as the various fundamental
620 type implementations or the signal system).
625 <!-- ##### ENUM GTypeDebugFlags ##### -->
627 The <type>GTypeDebugFlags</type> enumeration values can be passed to
628 g_type_init_with_debug_flags() to trigger debugging messages during runtime.
629 Note that the messages can also be triggered by setting the
630 <envar>GOBJECT_DEBUG</envar> environment variable to a ':'-separated list of
631 "objects" and "signals".
635 @G_TYPE_DEBUG_NONE: Print no messages.
636 @G_TYPE_DEBUG_OBJECTS: Print messages about object bookkeeping.
637 @G_TYPE_DEBUG_SIGNALS: Print messages about signal emissions.
638 @G_TYPE_DEBUG_MASK: Mask covering all debug flags.
640 <!-- ##### FUNCTION g_type_init_with_debug_flags ##### -->
642 Similar to g_type_init(), but additionally sets debug flags.
645 @debug_flags: Bitwise combination of #GTypeDebugFlags values for debugging purposes.
648 <!-- ##### FUNCTION g_type_name ##### -->
650 Returns the unique name that is assigned to a type ID (this is the preferred method
651 to find out whether a specific type has been registered for the passed in ID yet).
654 @type: Type to return name for.
655 @Returns: Static type name or %NULL.
658 <!-- ##### FUNCTION g_type_qname ##### -->
660 Return the corresponding quark of the type IDs name.
663 @type: Type to return quark of type name for.
664 @Returns: The type names quark or 0.
667 <!-- ##### FUNCTION g_type_from_name ##### -->
669 Lookup the type ID from a given type name, returns 0 if no type has been registered under this name
670 (this is the preferred method to find out by name whether a specific type has been registered yet).
673 @name: Type name to lookup.
674 @Returns: Corresponding type ID or 0.
677 <!-- ##### FUNCTION g_type_parent ##### -->
679 Return the direct parent type of the passed in type.
680 If the passed in type has no parent, i.e. is a fundamental type, 0 is returned.
683 @type: The derived type.
684 @Returns: The parent type.
687 <!-- ##### FUNCTION g_type_depth ##### -->
689 Returns the length of the ancestry of the passed in type. This includes the
690 type itself, so that e.g. a fundamental type has depth 1.
693 @type: A #GType value.
694 @Returns: The depth of @type.
697 <!-- ##### FUNCTION g_type_next_base ##### -->
699 Given a @leaf_type and a @root_type which is contained in its anchestry, return
700 the type that @root_type is the immediate parent of.
701 In other words, this function determines the type that is derived directly from
702 @root_type which is also a base class of @leaf_type. Given a root type and a
703 leaf type, this function can be used to determine the types and order in which
704 the leaf type is descended from the root type.
707 @leaf_type: Descendant of @root_type and the type to be returned.
708 @root_type: Immediate parent of the returned type.
709 @Returns: Immediate child of @root_type and anchestor of @leaf_type.
712 <!-- ##### FUNCTION g_type_is_a ##### -->
714 If @is_a_type is a derivable type, check whether @type is a descendant of @is_a_type.
715 If @is_a_type is an interface, check whether @type conforms to it.
718 @type: Type to check anchestry for.
719 @is_a_type: Possible anchestor of @type or interface @type could conform to.
720 @Returns: %TRUE if @type is_a @is_a_type holds true.
723 <!-- ##### FUNCTION g_type_class_ref ##### -->
725 Increments the reference count of the class structure belonging to
726 @type. This function will demand-create the class if it doesn't
730 @type: Type ID of a classed type.
731 @Returns: The #GTypeClass structure for the given type ID.
734 <!-- ##### FUNCTION g_type_class_peek ##### -->
736 This function is essentially the same as g_type_class_ref(), except that
737 the classes reference count isn't incremented. Therefore, this function
738 may return %NULL if the class of the type passed in does not currently
739 exist (hasn't been referenced before).
742 @type: Type ID of a classed type.
743 @Returns: The #GTypeClass structure for the given type ID or %NULL
744 if the class does not currently exist.
747 <!-- ##### FUNCTION g_type_class_peek_static ##### -->
749 A more efficient version of g_type_class_peek() which works only for
753 @type: Type ID of a classed type.
754 @Returns: The #GTypeClass structure for the given type ID or %NULL
755 if the class does not currently exist or is dynamically loaded.
759 <!-- ##### FUNCTION g_type_class_unref ##### -->
761 Decrements the reference count of the class structure being passed in.
762 Once the last reference count of a class has been released, classes
763 may be finalized by the type system, so further dereferencing of a
764 class pointer after g_type_class_unref() are invalid.
767 @g_class: The #GTypeClass structure to unreference.
770 <!-- ##### FUNCTION g_type_class_peek_parent ##### -->
772 This is a convenience function, often needed in class initializers.
773 It essentially takes the immediate parent type of the class passed in,
774 and returns the class structure thereof. Since derived classes hold
775 a reference count on their parent classes as long as they are instantiated,
776 the returned class will always exist. This function is essentially
780 g_type_class_peek (g_type_parent (G_TYPE_FROM_CLASS (g_class)));
785 @g_class: The #GTypeClass structure to retrieve the parent class for.
786 @Returns: The parent class of @g_class.
789 <!-- ##### FUNCTION g_type_class_add_private ##### -->
791 Registers a private structure for a instantiatable type;
792 when an object is allocated, the private structures for
793 the type and and all of its parent types are allocated
794 sequentially in the same memory block as the public
795 structures. This function should be called in the
796 type's class_init() function. The private structure can
797 be retrieved using the G_TYPE_INSTANCE_GET_PRIVATE() macro.
798 The following example shows attaching a private structure
799 <structname>MyObjectPrivate</structname> to an object
800 <structname>MyObject</structname> defined in the standard GObject
804 typedef struct _MyObjectPrivate MyObjectPrivate;
806 struct _MyObjectPrivate {
810 #define MY_OBJECT_GET_PRIVATE(o) \
811 (G_TYPE_INSTANCE_GET_PRIVATE ((o), MY_TYPE_OBJECT, MyObjectPrivate))
814 my_object_class_init (MyObjectClass *klass)
816 g_type_class_add_private (klass, sizeof (MyObjectPrivate));
820 my_object_get_some_field (MyObject *my_object)
822 MyObjectPrivate *priv = MY_OBJECT_GET_PRIVATE (my_object);
824 return priv->some_field;
828 @g_class: class structure for an instantiatable type
829 @private_size: size of private structure.
832 <!-- ##### FUNCTION g_type_interface_peek ##### -->
834 Returns the #GTypeInterface structure of an interface to which the passed in
838 @instance_class: A #GTypeClass structure.
839 @iface_type: An interface ID which this class conforms to.
840 @Returns: The #GTypeInterface structure of @iface_type, or %NULL if the
841 class is not instantiated.
844 <!-- ##### FUNCTION g_type_interface_peek_parent ##### -->
846 Returns the corresponding #GTypeInterface structure of the parent type
847 of the instance type to which @g_iface belongs. This is useful when
848 deriving the implementation of an interface from the parent type and
849 then possibly overriding some methods.
852 @g_iface: A #GTypeInterface structure.
853 @Returns: The corresponding #GTypeInterface structure of the parent type
854 of the instance type to which @g_iface belongs, or %NULL if the parent type
855 doesn't conform to the interface.
858 <!-- ##### FUNCTION g_type_default_interface_ref ##### -->
860 Increments the reference count for the interface type @g_type,
861 and returns the default interface vtable for the type.
864 If the type is not currently in use, then the default vtable
865 for the type will be created and initalized by calling
866 the base interface init and default vtable init functions for
867 the type (the @<structfield>base_init</structfield>
868 and <structfield>class_init</structfield> members of #GTypeInfo).
869 Calling g_type_default_interface_ref() is useful when you
870 want to make sure that signals and properties for an interface
874 @g_type: an interface type
875 @Returns: the default vtable for the interface; call
876 g_type_default_interface_unref() when you are done using
881 <!-- ##### FUNCTION g_type_default_interface_peek ##### -->
883 If the interface type @g_type is currently in use, returns
884 its default interface vtable.
887 @g_type: an interface type
888 @Returns: the default vtable for the interface; or %NULL
889 if the type is not currently in use.
893 <!-- ##### FUNCTION g_type_default_interface_unref ##### -->
895 Decrements the reference count for the type corresponding to the
896 interface default vtable @g_iface. If the type is dynamic, then
897 when no one is using the interface and all references have
898 been released, the finalize function for the interface's default
899 vtable (the <structfield>class_finalize</structfield> member of
900 #GTypeInfo) will be called.
903 @g_iface: the default vtable structure for a interface, as
904 returned by g_type_default_interface_ref()
908 <!-- ##### FUNCTION g_type_children ##### -->
910 Return a newly allocated and 0-terminated array of type IDs, listing the
911 child types of @type. The return value has to be g_free()ed after use.
914 @type: The parent type.
915 @n_children: Optional #guint pointer to contain the number of child types.
916 @Returns: Newly allocated and 0-terminated array of child types.
919 <!-- ##### FUNCTION g_type_interfaces ##### -->
921 Return a newly allocated and 0-terminated array of type IDs, listing the
922 interface types that @type conforms to. The return value has to be
923 g_free()ed after use.
926 @type: The type to list interface types for.
927 @n_interfaces: Optional #guint pointer to contain the number of interface types.
928 @Returns: Newly allocated and 0-terminated array of interface types.
931 <!-- ##### FUNCTION g_type_interface_prerequisites ##### -->
933 Returns the prerequisites of an interfaces type.
936 @interface_type: an interface type
937 @n_prerequisites: location to return the number of prerequisites, or %NULL
938 @Returns: a newly-allocated zero-terminated array of #GType containing
939 the prerequisites of @interface_type
943 <!-- ##### FUNCTION g_type_set_qdata ##### -->
945 Attaches arbitrary data to a type.
949 @quark: a #GQuark id to identify the data
953 <!-- ##### FUNCTION g_type_get_qdata ##### -->
955 Obtains data which has previously been attached to @type
956 with g_type_set_qdata().
960 @quark: a #GQuark id to identify the data
961 @Returns: the data, or %NULL if no data was found
964 <!-- ##### FUNCTION g_type_query ##### -->
966 Queries the type system for information about a specific type.
967 This function will fill in a user-provided structure to hold type-specific
968 information. If an invalid #GType is passed in, the @type member of the
969 #GTypeQuery is 0. All members filled into the #GTypeQuery structure should
970 be considered constant and have to be left untouched.
973 @type: the #GType value of a static, classed type.
974 @query: A user provided structure that is filled in with constant values
978 <!-- ##### STRUCT GTypeQuery ##### -->
980 A structure holding information for a specific type. It is
981 filled in by the g_type_query() function.
984 @type: the #GType value of the type.
985 @type_name: the name of the type.
986 @class_size: the size of the class structure.
987 @instance_size: the size of the instance structure.
989 <!-- ##### USER_FUNCTION GBaseInitFunc ##### -->
991 A callback function used by the type system to do base initialization
992 of the class structures of derived types. It is called as part of the
993 initialization process of all derived classes and should reallocate
994 or reset all dynamic class members copied over from the parent class.
995 Therefore class members, e.g. strings, that are not sufficiently
996 handled by a plain memory copy of the parent class into the derived class
997 have to be altered. See GClassInitFunc() for a discussion of the class
998 intialization process.
1001 @g_class: The #GTypeClass structure to initialize.
1004 <!-- ##### USER_FUNCTION GBaseFinalizeFunc ##### -->
1006 A callback function used by the type system to finalize those portions
1007 of a derived types class structure that were setup from the corresponding
1008 GBaseInitFunc() function. Class finalization basically works the inverse
1009 way in which class intialization is performed.
1010 See GClassInitFunc() for a discussion of the class intialization process.
1013 @g_class: The #GTypeClass structure to finalize.
1016 <!-- ##### USER_FUNCTION GClassInitFunc ##### -->
1018 A callback function used by the type system to initialize the class
1019 of a specific type. This function should initialize all static class
1021 The initialization process of a class involves:
1023 <varlistentry><term></term><listitem><para>
1024 1 - Copying common members from the parent class over to the
1025 derived class structure.
1026 </para></listitem></varlistentry>
1027 <varlistentry><term></term><listitem><para>
1028 2 - Zero initialization of the remaining members not copied
1029 over from the parent class.
1030 </para></listitem></varlistentry>
1031 <varlistentry><term></term><listitem><para>
1032 3 - Invocation of the GBaseInitFunc() initializers of all parent
1033 types and the class' type.
1034 </para></listitem></varlistentry>
1035 <varlistentry><term></term><listitem><para>
1036 4 - Invocation of the class' GClassInitFunc() initializer.
1037 </para></listitem></varlistentry>
1039 Since derived classes are partially initialized through a memory copy
1040 of the parent class, the general rule is that GBaseInitFunc() and
1041 GBaseFinalizeFunc() should take care of necessary reinitialization
1042 and release of those class members that were introduced by the type
1043 that specified these GBaseInitFunc()/GBaseFinalizeFunc().
1044 GClassInitFunc() should only care about initializing static
1045 class members, while dynamic class members (such as allocated strings
1046 or reference counted resources) are better handled by a GBaseInitFunc()
1047 for this type, so proper initialization of the dynamic class members
1048 is performed for class initialization of derived types as well.
1049 An example may help to correspond the intend of the different class
1054 GObjectClass parent_class;
1055 gint static_integer;
1056 gchar *dynamic_string;
1059 type_a_base_class_init (TypeAClass *class)
1061 class->dynamic_string = g_strdup ("some string");
1064 type_a_base_class_finalize (TypeAClass *class)
1066 g_free (class->dynamic_string);
1069 type_a_class_init (TypeAClass *class)
1071 class->static_integer = 42;
1075 TypeAClass parent_class;
1076 gfloat static_float;
1077 GString *dynamic_gstring;
1080 type_b_base_class_init (TypeBClass *class)
1082 class->dynamic_gstring = g_string_new ("some other string");
1085 type_b_base_class_finalize (TypeBClass *class)
1087 g_string_free (class->dynamic_gstring);
1090 type_b_class_init (TypeBClass *class)
1092 class->static_float = 3.14159265358979323846;
1095 Initialization of TypeBClass will first cause initialization of
1096 TypeAClass (derived classes reference their parent classes, see
1097 g_type_class_ref() on this).
1098 Initialization of TypeAClass roughly involves zero-initializing its fields,
1099 then calling its GBaseInitFunc() type_a_base_class_init() that allocates
1100 its dynamic members (dynamic_string) and finally calling its GClassInitFunc()
1101 type_a_class_init() to initialize its static members (static_integer).
1102 The first step in the initialization process of TypeBClass is then
1103 a plain memory copy of the contents of TypeAClass into TypeBClass and
1104 zero-initialization of the remaining fields in TypeBClass.
1105 The dynamic members of TypeAClass within TypeBClass now need
1106 reinitialization which is performed by calling type_a_base_class_init()
1107 with an argument of TypeBClass.
1108 After that, the GBaseInitFunc() of TypeBClass, type_b_base_class_init()
1109 is called to allocate the dynamic members of TypeBClass (dynamic_gstring),
1110 and finally the GClassInitFunc() of TypeBClass, type_b_class_init(),
1111 is called to complete the initialization process with the static members
1113 Corresponding finalization counter parts to the GBaseInitFunc() functions
1114 have to be provided to release allocated resources at class finalization
1118 @g_class: The #GTypeClass structure to initialize.
1119 @class_data: The @class_data member supplied via the #GTypeInfo structure.
1122 <!-- ##### USER_FUNCTION GClassFinalizeFunc ##### -->
1124 A callback function used by the type system to finalize a class.
1125 This function is rarely needed, as dynamically allocated class resources
1126 should be handled by GBaseInitFunc() and GBaseFinalizeFunc().
1127 Also, specification of a GClassFinalizeFunc() in the #GTypeInfo
1128 structure of a static type is invalid, because classes of static types
1129 will never be finalized (they are artificially kept alive when their
1130 reference count drops to zero).
1133 @g_class: The #GTypeClass structure to finalize.
1134 @class_data: The @class_data member supplied via the #GTypeInfo structure.
1137 <!-- ##### USER_FUNCTION GInstanceInitFunc ##### -->
1139 A callback function used by the type system to initialize a new
1140 instance of a type. This function initializes all instance members and
1141 allocates any resources required by it.
1142 Initialization of a derived instance involves calling all its parent
1143 types instance initializers, therefore the class member of the instance
1144 is altered during its initialization to always point to the class that
1145 belongs to the type the current initializer was introduced for.
1148 @instance: The instance to initialize.
1149 @g_class: The class of the type the instance is created for.
1152 <!-- ##### USER_FUNCTION GInterfaceInitFunc ##### -->
1154 A callback function used by the type system to initialize a new
1155 interface. This function should initialize all internal data and
1156 allocate any resources required by the interface.
1159 @g_iface: The interface structure to initialize.
1160 @iface_data: The @class_data supplied via the #GTypeInfo structure.
1163 <!-- ##### USER_FUNCTION GInterfaceFinalizeFunc ##### -->
1165 A callback function used by the type system to finalize an interface.
1166 This function should destroy any internal data and release any resources
1167 allocated by the corresponding GInterfaceInitFunc() function.
1170 @g_iface: The interface structure to finalize.
1171 @iface_data: The @class_data supplied via the #GTypeInfo structure.
1174 <!-- ##### USER_FUNCTION GTypeClassCacheFunc ##### -->
1176 A callback function which is called when the reference count of a class
1177 drops to zero. It may use g_type_class_ref() to prevent the class from
1178 being freed. You should not call g_type_class_unref() from a
1179 #GTypeClassCacheFunc function to prevent infinite recursion, use
1180 g_type_class_unref_uncached() instead.
1183 The functions have to check the class id passed in to figure
1184 whether they actually want to cache the class of this type, since all
1185 classes are routed through the same #GTypeClassCacheFunc chain.
1188 @cache_data: data that was given to the g_type_add_class_cache_func() call
1189 @g_class: The #GTypeClass structure which is unreferenced
1190 @Returns: %TRUE to stop further #GTypeClassCacheFunc<!-- -->s from being
1191 called, %FALSE to continue.
1194 <!-- ##### ENUM GTypeFlags ##### -->
1196 Bit masks used to check or determine characteristics of a type.
1199 @G_TYPE_FLAG_ABSTRACT: Indicates an abstract type. No instances can be
1200 created for an abstract type.
1201 @G_TYPE_FLAG_VALUE_ABSTRACT: Indicates an abstract value type, i.e. a type
1202 that introduces a value table, but can't be used for
1205 <!-- ##### ENUM GTypeFundamentalFlags ##### -->
1207 Bit masks used to check or determine specific characteristics of a
1211 @G_TYPE_FLAG_CLASSED: Indicates a classed type.
1212 @G_TYPE_FLAG_INSTANTIATABLE: Indicates an instantiable type (implies classed).
1213 @G_TYPE_FLAG_DERIVABLE: Indicates a flat derivable type.
1214 @G_TYPE_FLAG_DEEP_DERIVABLE: Indicates a deep derivable type (implies derivable).
1216 <!-- ##### FUNCTION g_type_register_static ##### -->
1218 Registers @type_name as the name of a new static type derived from
1219 @parent_type. The type system uses the information contained in the
1220 #GTypeInfo structure pointed to by @info to manage the type and its
1221 instances (if not abstract). The value of @flags determines the nature
1222 (e.g. abstract or not) of the type.
1225 @parent_type: Type which this type will be derived from.
1226 @type_name: 0-terminated string used as the name of the new type.
1227 @info: The #GTypeInfo structure for this type.
1228 @flags: Bitwise combination of #GTypeFlags values.
1229 @Returns: The new type identifier.
1232 <!-- ##### FUNCTION g_type_register_dynamic ##### -->
1234 Registers @type_name as the name of a new dynamic type derived from
1235 @parent_type. The type system uses the information contained in the
1236 #GTypePlugin structure pointed to by @plugin to manage the type and its
1237 instances (if not abstract). The value of @flags determines the nature
1238 (e.g. abstract or not) of the type.
1241 @parent_type: Type which this type will be derived from.
1242 @type_name: 0-terminated string used as the name of the new type.
1243 @plugin: The #GTypePlugin structure to retrieve the #GTypeInfo from.
1244 @flags: Bitwise combination of #GTypeFlags values.
1245 @Returns: The new type identifier or #G_TYPE_INVALID if registration failed.
1248 <!-- ##### FUNCTION g_type_register_fundamental ##### -->
1250 Registers @type_id as the predefined identifier and @type_name as the
1251 name of a fundamental type. The type system uses the information
1252 contained in the #GTypeInfo structure pointed to by @info and the
1253 #GTypeFundamentalInfo structure pointed to by @finfo to manage the
1254 type and its instances. The value of @flags determines additional
1255 characteristics of the fundamental type.
1258 @type_id: A predefined #GTypeFundamentals value.
1259 @type_name: 0-terminated string used as the name of the new type.
1260 @info: The #GTypeInfo structure for this type.
1261 @finfo: The #GTypeFundamentalInfo structure for this type.
1262 @flags: Bitwise combination of #GTypeFlags values.
1263 @Returns: The predefined type identifier.
1266 <!-- ##### FUNCTION g_type_add_interface_static ##### -->
1268 Adds the static @interface_type to @instantiable_type. The information
1269 contained in the #GTypeInterfaceInfo structure pointed to by @info
1270 is used to manage the relationship.
1273 @instance_type: #GType value of an instantiable type.
1274 @interface_type: #GType value of an interface type.
1275 @info: The #GInterfaceInfo structure for this
1276 (@instance_type, @interface_type) combination.
1279 <!-- ##### FUNCTION g_type_add_interface_dynamic ##### -->
1281 Adds the dynamic @interface_type to @instantiable_type. The information
1282 contained in the #GTypePlugin structure pointed to by @plugin
1283 is used to manage the relationship.
1286 @instance_type: the #GType value of an instantiable type.
1287 @interface_type: the #GType value of an interface type.
1288 @plugin: the #GTypePlugin structure to retrieve the #GInterfaceInfo from.
1291 <!-- ##### FUNCTION g_type_interface_add_prerequisite ##### -->
1293 Adds @prerequisite_type to the list of prerequisites of @interface_type.
1294 This means that any type implementing @interface_type must also implement
1295 @prerequisite_type. Prerequisites can be thought of as an alternative to
1296 interface derivation (which GType doesn't support). An interface can have
1297 at most one instantiatable prerequisite type.
1300 @interface_type: #GType value of an interface type.
1301 @prerequisite_type: #GType value of an interface or instantiatable type.
1304 <!-- ##### FUNCTION g_type_get_plugin ##### -->
1306 Returns the #GTypePlugin structure for @type or
1307 %NULL if @type does not have a #GTypePlugin structure.
1310 @type: The #GType to retrieve the plugin for.
1311 @Returns: The corresponding plugin if @type is a dynamic type,
1315 <!-- ##### FUNCTION g_type_interface_get_plugin ##### -->
1317 Returns the #GTypePlugin structure for the dynamic interface
1318 @interface_type which has been added to @instance_type, or
1319 %NULL if @interface_type has not been added to @instance_type or does
1320 not have a #GTypePlugin structure. See g_type_add_interface_dynamic().
1323 @instance_type: the #GType value of an instantiatable type.
1324 @interface_type: the #GType value of an interface type.
1325 @Returns: the #GTypePlugin for the dynamic interface @interface_type
1329 <!-- ##### FUNCTION g_type_fundamental_next ##### -->
1331 Returns the next free fundamental type id which can be used to
1332 register a new fundamental type with g_type_register_fundamental().
1333 The returned type ID represents the highest currently registered
1334 fundamental type identifier.
1338 @Returns: The nextmost fundamental type ID to be registered,
1339 or 0 if the type system ran out of fundamental type IDs.
1342 <!-- ##### FUNCTION g_type_fundamental ##### -->
1344 Internal function, used to extract the fundamental type ID portion.
1345 use G_TYPE_FUNDAMENTAL() instead.
1348 @type_id: valid type ID
1349 @Returns: fundamental type ID
1352 <!-- ##### FUNCTION g_type_create_instance ##### -->
1354 Creates and initializes an instance of @type if @type is valid and can
1355 be instantiated. The type system only performs basic allocation and
1356 structure setups for instances, actual instance creation should happen
1357 through functions supplied by the type's fundamental type implementation.
1358 So use of g_type_create_instance() is reserved for implementators of
1359 fundamental types only. E.g. instances of the #GObject hierarchy
1360 should be created via g_object_new() and <emphasis>never</emphasis>
1361 directly through g_type_create_instance() which doesn't handle
1362 things like singleton objects or object construction.
1363 Note: Do <emphasis>not</emphasis> use this function, unless you're
1364 implementing a fundamental type. Also language bindings should <emphasis>not</emphasis>
1365 use this function but g_object_new() instead.
1368 @type: An instantiatable type to create an instance for.
1369 @Returns: An allocated and initialized instance, subject to further
1370 treatment by the fundamental type implementation.
1373 <!-- ##### FUNCTION g_type_free_instance ##### -->
1375 Frees an instance of a type, returning it to the instance pool for the type,
1379 Like g_type_create_instance(), this function is reserved for implementors of
1383 @instance: an instance of a type.
1386 <!-- ##### FUNCTION g_type_add_class_cache_func ##### -->
1388 Adds a #GTypeClassCacheFunc to be called before the reference count of a class
1389 goes from one to zero. This can be used to prevent premature class destruction.
1390 All installed #GTypeClassCacheFunc functions will be chained until one of them
1391 returns %TRUE. The functions have to check the class id passed in to figure
1392 whether they actually want to cache the class of this type, since all classes
1393 are routed through the same #GTypeClassCacheFunc chain.
1396 @cache_data: data to be passed to @cache_func
1397 @cache_func: a #GTypeClassCacheFunc
1400 <!-- ##### FUNCTION g_type_remove_class_cache_func ##### -->
1402 Removes a previously installed #GTypeClassCacheFunc. The cache maintained
1403 by @cache_func has to be empty when calling g_type_remove_class_cache_func()
1407 @cache_data: data that was given when adding @cache_func
1408 @cache_func: a #GTypeClassCacheFunc
1411 <!-- ##### FUNCTION g_type_class_unref_uncached ##### -->
1413 A variant of g_type_class_unref() for use in #GTypeClassCacheFunc
1414 implementations. It unreferences a class without consulting the chain
1415 of #GTypeClassCacheFunc<!-- -->s, avoiding the recursion which would occur
1419 @g_class: The #GTypeClass structure to unreference.
1422 <!-- ##### FUNCTION g_type_add_interface_check ##### -->
1424 Adds a function to be called after an interface vtable is
1425 initialized for any class. That is, after the @interface_init
1426 member of #GInterfaceInfo has been called.
1429 This function is useful when you want to check an invariant
1430 that depends on the interfaces of a class. For instance,
1431 the implementation of #GObject uses this facility to check
1432 that an object implements all of the properties that are
1433 defined on its interfaces.
1436 @check_data: data to pass to @check_func
1437 @check_func: function to be called after each interface
1442 <!-- ##### FUNCTION g_type_remove_interface_check ##### -->
1444 Removes an interface check function added with
1445 g_type_add_interface_check().
1448 @check_data: callback data passed to g_type_add_interface_check()
1449 @check_func: callback function passed to g_type_add_interface_check()
1453 <!-- ##### USER_FUNCTION GTypeInterfaceCheckFunc ##### -->
1455 A callback called after an interface vtable is initialized.
1456 See g_type_add_interface_check().
1459 @check_data: data passed to g_type_add_interface_check().
1460 @g_iface: the interface that has been initialized
1464 <!-- ##### FUNCTION g_type_value_table_peek ##### -->
1466 Returns the location of the #GTypeValueTable associated with @type.
1467 <emphasis>Note, this function should only be used from source code
1468 that implements or has internal knowledge of the implementation of
1472 @type: A #GType value.
1473 @Returns: Location of the #GTypeValueTable associated with @type or
1474 %NULL if there is no #GTypeValueTable associated with @type.
1477 <!-- ##### MACRO G_DEFINE_TYPE ##### -->
1479 A convenience macro for type implementations, which declares a
1480 class initialization function, an instance initialization function (see #GTypeInfo for information about
1481 these) and a static variable named @t_n<!-- -->_parent_class pointing to the parent class. Furthermore, it defines
1482 a *_get_type() function. See G_DEFINE_TYPE_EXTENDED() for an example.
1485 @TN: The name of the new type, in Camel case.
1486 @t_n: The name of the new type, in lowercase, with words
1488 @T_P: The #GType of the parent type.
1492 <!-- ##### MACRO G_DEFINE_TYPE_WITH_CODE ##### -->
1494 A convenience macro for type implementations.
1495 Similar to G_DEFINE_TYPE(), but allows to insert custom code into the
1496 *_get_type() function, e.g. interface implementations via G_IMPLEMENT_INTERFACE().
1497 See G_DEFINE_TYPE_EXTENDED() for an example.
1500 @TN: The name of the new type, in Camel case.
1501 @t_n: The name of the new type in lowercase, with words separated by '_'.
1502 @T_P: The #GType of the parent type.
1503 @_C_: Custom code that gets inserted in the *_get_type() function.
1507 <!-- ##### MACRO G_DEFINE_ABSTRACT_TYPE ##### -->
1509 A convenience macro for type implementations.
1510 Similar to G_DEFINE_TYPE(), but defines an abstract type.
1511 See G_DEFINE_TYPE_EXTENDED() for an example.
1514 @TN: The name of the new type, in Camel case.
1515 @t_n: The name of the new type, in lowercase, with words
1517 @T_P: The #GType of the parent type.
1521 <!-- ##### MACRO G_DEFINE_ABSTRACT_TYPE_WITH_CODE ##### -->
1523 A convenience macro for type implementations.
1524 Similar to G_DEFINE_TYPE_WITH_CODE(), but defines an abstract type and allows to
1525 insert custom code into the *_get_type() function, e.g. interface implementations
1526 via G_IMPLEMENT_INTERFACE(). See G_DEFINE_TYPE_EXTENDED() for an example.
1529 @TN: The name of the new type, in Camel case.
1530 @t_n: The name of the new type, in lowercase, with words
1532 @T_P: The #GType of the parent type.
1533 @_C_: Custom code that gets inserted in the @type_name_get_type() function.
1537 <!-- ##### MACRO G_IMPLEMENT_INTERFACE ##### -->
1539 A convenience macro to ease interface addition in the @_C_ section
1540 of G_DEFINE_TYPE_WITH_CODE() or G_DEFINE_ABSTRACT_TYPE_WITH_CODE().
1541 See G_DEFINE_TYPE_EXTENDED() for an example.
1544 Note that this macro can only be used together with the G_DEFINE_TYPE_*
1545 macros, since it depends on variable names from those macros.
1548 @TYPE_IFACE: The #GType of the interface to add
1549 @iface_init: The interface init function
1553 <!-- ##### MACRO G_DEFINE_TYPE_EXTENDED ##### -->
1555 The most general convenience macro for type implementations, on which
1556 G_DEFINE_TYPE(), etc are based.
1558 <informalexample><programlisting>
1559 G_DEFINE_TYPE_EXTENDED (GtkGadget,
1563 G_IMPLEMENT_INTERFACE (TYPE_GIZMO,
1564 gtk_gadget_gizmo_init));
1568 static void gtk_gadget_init (GtkGadget *self);
1569 static void gtk_gadget_class_init (GtkGadgetClass *klass);
1570 static gpointer gtk_gadget_parent_class = NULL;
1571 static void gtk_gadget_class_intern_init (gpointer klass)
1573 gtk_gadget_parent_class = g_type_class_peek_parent (klass);
1574 gtk_gadget_class_init ((GtkGadgetClass*) klass);
1578 gtk_gadget_get_type (void)
1580 static GType g_define_type_id = 0;
1581 if (G_UNLIKELY (g_define_type_id == 0))
1583 static const GTypeInfo g_define_type_info = {
1584 sizeof (GtkGadgetClass),
1585 (GBaseInitFunc) NULL,
1586 (GBaseFinalizeFunc) NULL,
1587 (GClassInitFunc) gtk_gadget_class_intern_init,
1588 (GClassFinalizeFunc) NULL,
1589 NULL, /* class_data */
1591 0, /* n_preallocs */
1592 (GInstanceInitFunc) gtk_gadget_init,
1594 g_define_type_id = g_type_register_static (GTK_TYPE_WIDGET, "GtkGadget", &g_define_type_info, 0);
1596 static const GInterfaceInfo g_implement_interface_info = {
1597 (GInterfaceInitFunc) gtk_gadget_gizmo_init
1599 g_type_add_interface_static (g_define_type_id, TYPE_GIZMO, &g_implement_interface_info);
1602 return g_define_type_id;
1605 The only pieces which have to be manually provided are the definitions of the
1606 instance and class structure and the definitions of the instance and class
1610 @TypeName: The name of the new type, in Camel case.
1611 @type_name: The name of the new type, in lowercase, with words
1613 @TYPE_PARENT: The #GType of the parent type.
1614 @flags: #GTypeFlags to pass to g_type_register_static()
1615 @CODE: Custom code that gets inserted in the *_get_type() function.
1619 <!-- ##### MACRO G_TYPE_INVALID ##### -->
1621 An invalid #GType, used as error return value in some functions which return
1627 <!-- ##### MACRO G_TYPE_NONE ##### -->
1629 A fundamental type which is used as a replacement for the C
1630 <literal>void</literal> return type.
1635 <!-- ##### MACRO G_TYPE_INTERFACE ##### -->
1637 The fundamental type from which all interfaces are derived.
1642 <!-- ##### MACRO G_TYPE_CHAR ##### -->
1644 The fundamental type corresponding to #gchar.
1649 <!-- ##### MACRO G_TYPE_UCHAR ##### -->
1651 The fundamental type corresponding to #guchar.
1656 <!-- ##### MACRO G_TYPE_BOOLEAN ##### -->
1658 The fundamental type corresponding to #gboolean.
1663 <!-- ##### MACRO G_TYPE_INT ##### -->
1665 The fundamental type corresponding to #gint.
1670 <!-- ##### MACRO G_TYPE_UINT ##### -->
1672 The fundamental type corresponding to #guint.
1677 <!-- ##### MACRO G_TYPE_LONG ##### -->
1679 The fundamental type corresponding to #glong.
1684 <!-- ##### MACRO G_TYPE_ULONG ##### -->
1686 The fundamental type corresponding to #gulong.
1691 <!-- ##### MACRO G_TYPE_INT64 ##### -->
1693 The fundamental type corresponding to #gint64.
1698 <!-- ##### MACRO G_TYPE_UINT64 ##### -->
1700 The fundamental type corresponding to #guint64.
1705 <!-- ##### MACRO G_TYPE_ENUM ##### -->
1707 The fundamental type from which all enumeration types are derived.
1712 <!-- ##### MACRO G_TYPE_FLAGS ##### -->
1714 The fundamental type from which all flags types are derived.
1719 <!-- ##### MACRO G_TYPE_FLOAT ##### -->
1721 The fundamental type corresponding to #gfloat.
1726 <!-- ##### MACRO G_TYPE_DOUBLE ##### -->
1728 The fundamental type corresponding to #gdouble.
1733 <!-- ##### MACRO G_TYPE_STRING ##### -->
1735 The fundamental type corresponding to nul-terminated C strings.
1740 <!-- ##### MACRO G_TYPE_POINTER ##### -->
1742 The fundamental type corresponding to #gpointer.
1747 <!-- ##### MACRO G_TYPE_BOXED ##### -->
1749 The fundamental type from which all boxed types are derived.
1754 <!-- ##### MACRO G_TYPE_PARAM ##### -->
1756 The fundamental type from which all #GParamSpec types are derived.
1761 <!-- ##### MACRO G_TYPE_OBJECT ##### -->
1763 The fundamental type for #GObject.
1768 <!-- ##### MACRO G_TYPE_RESERVED_GLIB_FIRST ##### -->
1770 First fundamental type number to create a new fundamental type id with
1771 G_TYPE_MAKE_FUNDAMENTAL() reserved for GLib.
1776 <!-- ##### MACRO G_TYPE_RESERVED_GLIB_LAST ##### -->
1778 Last fundamental type number reserved for GLib.
1783 <!-- ##### MACRO G_TYPE_RESERVED_BSE_FIRST ##### -->
1785 First fundamental type number to create a new fundamental type id with
1786 G_TYPE_MAKE_FUNDAMENTAL() reserved for BSE.
1791 <!-- ##### MACRO G_TYPE_RESERVED_BSE_LAST ##### -->
1793 Last fundamental type number reserved for BSE.
1798 <!-- ##### MACRO G_TYPE_RESERVED_USER_FIRST ##### -->
1800 First available fundamental type number to create new fundamental
1801 type id with G_TYPE_MAKE_FUNDAMENTAL().
1807 sgml-parent-document: ("../gobject-docs.sgml" "book" "refsect2" "")